The invention relates generally to the field of robotics and more particularly to an apparatus for gripping an object between robotic fingers.
In the field of robotic grippers, most systems provide for gripping movement of a finger(s) by driving pistons which are connected to a cam or a lever which is, in turn, coupled to the moveable finger or fingers. Generally, the primary actuation of the piston is effected by pneumatics, wherein a pneumatic pump is attached to an air cylinder for alternately supplying air pressure at a first connection point to drive one or more pistons in a direction toward the fingers, which moves the fingers outwardly to an open position, and then supplying air to an alternate connection point to drive the one or more pistons away from the fingers, to thereby move the fingers inwardly to a closed position.
A primary disadvantage of the prior art piston-driven grippers is the complexity of the piston-cam-finger system or piston-lever-finger system which necessarily increases both the size and the cost of the gripper. In addition, the prior art piston-driven grippers generally have a fixed stroke such that a gripper is calibrated for a single use (e.g., for gripping 200 mm wafers) and cannot be adjusted for gripping an item that is sized differently than the calibrated size. Finally, a disadvantage of the prior art piston-driven grippers is that such grippers have a significant number of moving parts which may potentially deposit contaminants on or in the item to be gripped. Accordingly, robotic grippers are in need of improvement.
The present invention provides a robotic gripper having a rail, a rotary actuator, and at least one slide component moveably mounted on the rail and operatively coupled to the rotary actuator. A first gripping finger is mounted to the at least one slide component so as to move therewith, and a second gripping finger is positioned so that an object may be selectively gripped and ungripped by the first and the second gripping fingers.
In a first aspect a magnet is coupled to the rotary actuator and a magnet is coupled to the at least one slide component so that rotation of the rotary actuator selectively causes attraction or repulsion of the magnet coupled to the at least one slide component, thus causing the gripping fingers selectively to assume open and closed positions.
In a further aspect, the rotary actuator comprises a rotatable arm. A first extension arm is coupled to the rotatable arm and to the first slide component so that the first slide component moves in a first and a second direction along the rail as the rotatable arm rotates in a first and a second direction, respectively. An object is gripped by placing the gripping fingers adjacent an object to be gripped and by rotating the actuator such that the gripping fingers grip the object.